Method of and apparatus for recording data on optical recording medium

ABSTRACT

A method of and apparatus for recording data on an optical recording medium form a mark or a space by using a recording waveform having an erase pattern containing a multi-pulse. The method and the apparatus prevent distortion of the mark or the space and improve a mark shape such that a recording/reproducing characteristic of the optical recording medium is improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of prior U.S. application Ser. No.10/256,244, filed Sep. 27, 2002, now U.S. Pat. No. 7,525,890, whichclaims the benefit of Korean Patent Application Nos. 2001-61039, filedSep. 29, 2001, and 2001-80541, filed Dec. 18, 2001, in the KoreanIntellectual Property Office, and U.S. Provisional Application Nos.60/327,305, filed Oct. 9, 2001, and 60/373,377, filed Apr. 18, 2002, thedisclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The following description relates to a method of and apparatus forrecording data on an optical recording medium, and more particularly, toa method and apparatus in which digital data is recorded on an opticaldisc by forming a mark on the optical disc.

2. Description of the Related Art

Data are recorded on an optical disc which is one type of opticalrecording media, in a form of a mark on a track formed on the opticaldisc. A mark is formed as a pit in a read-only disc, such as a CompactDisc-Read Only Memory (CD-ROM) and a Digital Versatile Disc-Read OnlyMemory (DVD-ROM). In a recordable disc, such as a CD-R/RW and aDVD-R/RW/RAM, a phase-change film which is changed into a crystallinephase or an amorphous phase is formed on a recording layer, and a markis formed by a phase change of the phase-change film.

Methods of recording data can be divided into a mark edge recordingmethod and a mark position recording method. According to the markposition recording method, a signal of an amplitude of a detected RadioFrequency (RF) signal is changed from negative to positive or frompositive to negative at a location on which a mark is recorded.According to the mark edge recording method, the signal of the amplitudeof the detected RF signal is changed from negative to positive or frompositive to negative at both edges of the mark. Therefore, recording theedges of the mark is an important factor in improving quality of asignal reproduced from the optical disc.

However, in a disc on which the phase-change film is coated, it is shownthat a shape of a trailing edge of the mark recorded according to aprior art recording method changes according to a length of the mark oran interval between the marks, i.e., a space. That is, the trailing edgeof the mark is formed greater than a leading edge of the mark such thatrecording/reproducing characteristics of the disc are degraded. If arecording mark is relatively long, the recording/reproducingcharacteristics are more degraded.

FIGS. 1A-1E are reference diagrams of recording waveforms (a), (b), and(c) to record a Non Return to Zero Inverted (NRZI) data signal accordingto the prior art. The recording waveform (a) is used for recording theNRZI data signal on a DVD-RAM, the recording waveforms (b) and (c) arefor a DVD-RW. Here, T denotes a cycle of a reference clock. According tothe mark edge recording method, a high level of NRZI data is recorded asa mark and a low level of NRZI data is formed as a space. A portion ofthe recording waveform used in recording the mark is referred to as arecording pattern, and another portion of the recording waveform used informing the space (in erasing the mark) is referred to as an erasepattern. The prior art recording waveforms (a), (b) and (c) use amulti-pulse as the recording pattern, and a power of the erase patternis maintained constant in a predetermined DC level for an interval E asshown in FIG. 1E.

Since the DC level of the erase pattern included in the prior artrecording waveform is maintained constant for a predetermined period oftime, 0˜200° C. heat is continuously applied to a corresponding area toform the space. Therefore, if recording is repeatedly performed, a shapeof the mark is degraded and distorted such that therecording/reproducing characteristics of the optical disc are degraded.In particular, a development toward a high density and a high line speedfor recording more data on the optical disc makes the clock cycle Tshorter, and therefore a heat interference between pulses forming therecording waveform increases to cause more degradation of therecording/reproducing characteristics of the optical disc.

Meanwhile, in the prior art, the different recording waveforms are usedaccording to the kinds of the optical discs and specifications, such asDVD-RAM and DVD-RW, because characteristics of recording films of theoptical discs are different. In particular, due to the fact that thedifferent recording waveforms should be used for each kind of theoptical discs, a problem occurs in manufacturing a multi-drive which canrecord/reproduce all specifications of the optical discs because themulti-drive should accommodate a variety of the different recordingwaveforms. The problem causes an increase in cost.

SUMMARY OF THE INVENTION

To solve the above and/or other problems, it is a general aspect toprovide a recording method and apparatus in which distortion of shapesof a leading edge and a trailing edge of a mark and degradation of themark caused by repeated recording operations can be prevented.

It is another general aspect to provide a recording method and apparatusin which data is recorded by a recording waveform having an erasepattern which can improve a shape of a mark or a space.

It is yet another general aspect to provide a recording method andapparatus in which data is recorded by a recording waveform which can beapplied to a disc having a recording film with a variety ofcharacteristics.

Other features and aspects may be apparent from the following detaileddescription, the drawings, and the claims.

In one general aspect, there is provided a method of recording data onan optical recording medium. The method includes forming a mark or aspace by using a recording waveform having an erase pattern containing amulti-pulse.

The method may further provide that data is recorded according to a RunLength Limited (RLL) (2, 10) process in which 2 and 10 are a minimumlength and a maximum length of the mark or space, respectively, a firstlevel of a predetermined Non Return to Zero Inverted (NRZI) data signalis recorded as the mark, and a second level of the predetermined NRZIdata signal is recorded as the space.

Also, in another aspect, there is provided a method of recording data onthe optical recording medium. The method includes generating a channelmodulated digital data (NRZI data) signal, generating the recordingwaveform having the erase pattern containing the multi-pulse and therecording pattern, and forming the first level of the charnel modulatedigital data signal as the mark and forming the second level of thechannel modulate digital data signal as the space by using the generatedrecording waveform.

The method may be based on the Run Length Limited (RLL) (2, 10) or RLL(1, 7) process in which 1 and 7 are the minimum length and the maximumlength of the mark or space.

The method may further provide that a power level of a leading pulse ofthe erase pattern is a low level of the multi-pulse and another powerlevel of a trailing pulse is a high level of the multi-pulse.Alternatively, the power level of the leading pulse of the erase patternmay be the high level of the multi-pulse, and the power level of thetrailing pulse may be the high level of the multi-pulse. The power levelof the leading pulse of the erase pattern may be the low level of themulti-pulse and the power level of the trailing pulse may be the lowlevel of the multi-pulse. The power level of the leading pulse of theerase pattern may be the high level of the multi-pulse and the powerlevel of the trailing pulse may be the low level of the multi-pulse.

The method may further provide that a ratio of a duration time of thehigh level and another duration time of the low level of the multi-pulseis substantially 1:1, and the duration time of the high level is half aclock cycle.

It is possible that in the generating of the channel modulated digitaldata, the first level of the NRZI data signal is formed as the mark, andin the generating of the recording waveform, the second level of theNRZI data signal is formed as the space.

The recording waveform includes a cooling pulse, and the erase patternincludes a part of the cooling pulse. It is possible that if an endingtime of the cooling pulse is less than or greater than 0.5 Ts from thetrailing edge of the NRZI data, the duration time of the leading pulseforming the erase pattern increases over 0.5 Ts when T is a cycle of areference clock signal.

The method may further provide that a unit pulse constituting orincluded in the multi-pulse has a high level and a low level that areadjusted by the duration time of the leading pulse of the recordingpattern.

The method may further provide that the recording pattern has at leasttwo power levels.

Also, in another aspect, there is provided an apparatus for recordingdata on the optical recording medium. The apparatus includes a recordingwaveform generating unit which generates the recording waveform havingthe erase pattern containing the multi-pulse and the recording pattern,and a pickup unit which applies light to the optical recording mediumaccording to the generated recording waveform so that the mark or thespace is formed.

The apparatus also may further provide a channel modulation unit whichchannel-modulates input data received from an outside source and outputsthe generated NRZI data signal to the recording waveform generatingunit.

The apparatus may further provide that the pickup unit includes a motorwhich rotates the optical recording medium, an optical head whichapplies a laser beam to the optical recording medium or receives thelaser beam reflected from the optical recording medium, a servo circuitwhich servo-controls the motor and the optical head, and a laser drivingcircuit which drives a laser device installed in the optical head togenerate the laser beam.

BRIEF DESCRIPTION OF THE DRAWINGS

The above features and/or aspects will become more apparent and morereadily appreciated from the following description, taken in conjunctionwith the accompanying drawings of which:

FIGS. 1A-1E are reference diagrams illustrating examples of recordingwaveforms according to related art;

FIG. 2 is a block diagram illustrating an example of a recordingapparatus;

FIG. 3 shows an example of an implementation of the recording apparatusof FIG. 2;

FIGS. 4A-4C show an example of a waveform generated by a recordingwaveform generating circuit of the recording apparatus of FIG. 3;

FIGS. 5A-5C show another example of a waveform generated by therecording waveform generating circuit of the recording apparatus of FIG.3;

FIGS. 6A through 6E are waveforms explaining four types of erasepatterns;

FIGS. 7A and 7D are other examples of the erase pattern of FIG. 6B;

FIGS. 8A through 10C are shapes of marks recorded in a simulation;

FIGS. 11A through 15 are graphs showing characteristics of a DVD-RAM;

FIGS. 16A through 20 are graphs showing characteristics of a DVD-RW; and

FIG. 21 is a flowchart showing an example of a recording method.

DETAILED DESCRIPTION

Reference will now be made in detail to various examples of methods,apparatuses, and/or systems, examples of which are illustrated in theaccompanying drawings, wherein like reference numerals refer to the likeelements throughout. The examples are described in order to explaingeneral aspects by referring to the figures.

FIG. 2 is a block diagram illustrating an example of a recordingapparatus. Referring to FIG. 2, the recording apparatus which forms amark or a space on an optical recording medium (optical disc) 200, has apickup unit 1, a recording waveform generating circuit 2, and a channelmodulator 3.

The channel modulator 3 modulates input data which is input from anoutside source into a channel bit stream, such as a Non Return to ZeroInverted (NRZI) data signal. The recording waveform generating circuit 2receives the channel bit stream and generates a recording waveform torecord the received channel bit stream. The recording waveform generatedhas an erase pattern having an erase multi-pulse. The recording waveformwill be explained later in detail. The pickup unit 1 applies light (alaser beam) to the optical recording medium 200 according to thegenerated recording waveform so as to form the mark or the space.

FIG. 3 shows an example of an implementation of the recording apparatusof FIG. 2. The same blocks will be indicated by the same referencenumerals, and the same explanation will be omitted. Referring to FIG. 3,the recording apparatus includes the pickup unit 1, the recordingwaveform generating circuit 2, and the channel modulator 3. The pickupunit 1 has a motor 11 rotating the optical disc 200, an optical head 13receiving the light reflected from the optical disc 200, a servo circuit12 controlling the motor and the optical head, and a laser drivingcircuit 14 driving a laser device (not shown) installed in the opticalhead 13 to generate the light.

The channel modulator 3 modulates the input data into the channel bitstream and outputs the NRZI data signal. The recording waveformgenerating circuit 2 generates the recording waveform to record the NRZIdata signal and provides the recording waveform to the laser drivingcircuit 14. The laser driving circuit 14 forms the mark or the space bycontrolling the laser device in accordance with the received recordingwaveform.

FIGS. 4A-4C show an example of the recording waveforms generated by therecording waveform generating circuit 2. Referring to FIGS. 4A-4C, theNRZI data signal is changed from the input data according to amodulation method of the channel modulator 3. That is, if the modulationmethod is a Run Length Limited (RLL) (2, 10) series method. That is,according to an Eight to Fourteen Modulation (EFM) method, an Eight toFourteen Modulation plus (EFM+) method, a D(8-15) method, and a Dualmodulation method, a minimum length of the mark or the space is 3 Ts anda maximum length of the mark or the space is 11 Ts, where T is a cycleof a clock signal as shown in FIG. 4A, The D(8-15) method is amodulation method disclosed in “Optical Disc Recording System of 25 GBCapacity” announced by Matsushita in Optical Data Storage (ODS) 2001.The Dual modulation method is disclosed in Korean Patent Application No.99-42032 titled “An RLL code allocation method, modulation anddemodulation method, and demodulation apparatus having improved DCcontrolling capability,” filed by the present applicant on Sep. 30,1999, and published on Nov. 25, 2000. If data is recorded using theRLL(1, 7) series method, the minimum length is 2 Ts, and the maximumlength is 8 Ts.

When a high level of the NRZI data signal is formed as the mark and alow level of the NRZI data signal is formed as the space, the recordingwaveform includes a recording pattern to record a mark of a 7 T length,an erase pattern to form a space of a 3 T length, and another recordingpattern to record a mark of a 3 T length as shown in FIG. 4B.

The recording pattern includes a pulse train, e.g., a multi-pulse. Also,the erase pattern is formed with another pulse train, e.g., anothermulti-pulse (erase multi-pulse) having an interval F as shown in FIG.4C. Tmp indicates a width of a pulse of the multi-pulse of the recordingpattern. Here, the multi-pulse indicates at least one pulse having thesame width and power. However, it is understood that general aspects arenot limited thereto. That is, the width and the power of each pulse ofthe multi-pulse may vary. In one general aspect, Tmp is 0.5 Ts. Tlpindicates a width of a last pulse of the recording pattern. Tclindicates a width (duration time) of a cooling pulse. The cooling pulseextends from the recording pattern to the erase pattern. Temp indicatesa width of a pulse of the multi-pulse of the erase pattern. In onegeneral aspect, Temp is 0.5 Ts. Tsfp indicates a period from a pointwhere the NRZI data signal is transited from the low level to the highlevel at a point (start point of a first pulse) when the first pulseforming the recording pattern starts. Tsfp is under an influence of apower level of the erase pattern. That is, as shown in FIG. 4C, if Tsfpis greater than 0.5 Ts and the multi-pulse contained in the erasepattern ends at low level Pb1, a next Tsfp starts from a high level Pb2of the multi-pulse. Meanwhile, if Tsfp is less than 0.5 Ts and themulti-pulse contained in the erase pattern ends at a low level Pb1, thenext Tsfp maintains the low level Pb1 of the multi-pulse.

FIGS. 5A-5C show another example of waveforms generated by the recordingwaveform generating circuit 2. Referring to FIG. 5B, when the high levelof the NRZI data signal is formed as the mark, and the low level isformed as the space, the recording waveform includes the recordingpattern to record a mark of a 7 T length, the erase pattern to form aspace of a 5 T length, and the recording pattern to record a mark of a 3T length.

The recording pattern includes the pulse train. Also, the erase patternis formed with the pulse train, e.g., the multi-pulse (erasemulti-pulse) having an interval G as shown in FIG. 5C. Tmp indicates thewidth of the multi-pulse forming the recording pattern. Here, themulti-pulse indicates at least one pulse having the same width andpower. However, it is understood that general aspects are not limitedthereto. That is, the width and the power of each pulse of themulti-pulse may vary. In one general aspect, Tmp is 0.5 Ts. Tlpindicates the width of the last pulse forming a recording pattern. Tclindicates the width (duration time) of the cooling pulse. The coolingpulse extends from the recording pattern to the erase pattern. Tempindicates the width of the erase multi-pulse constituting the erasepattern. In one general aspect, Temp is 0.5 Ts. Tsfp indicates a periodfrom a point where the NRZI data is transited from the low level to thehigh level at the point (start point of the first pulse) when the firstpulse constituting the recording pattern starts. Tsfp is determined inresponse to the power level of the erase pattern. That is, as shown inFIG. 5C, if Tsfp is greater than 0.5 Ts and the multi-pulse contained inthe erase pattern ends at low level Pb1, the next Tsfp starts from thehigh level Pb2 of the multi-pulse. Meanwhile, if Tsfp is less than 0.5Ts and the multi-pulse contained in an erase pattern ends at the lowlevel Pb1, the next Tsfp maintains the low level Pb1 of the multi-pulse.

FIGS. 6A through 6E are waveforms explaining four types of the erasepatterns. Referring to FIGS. 6A through 6E, the erase patterns aredivided into the four types: (a) LH, (b) HH, (c) HL, and (d) LL.Differences between the power levels of the erase patterns are markedwith circles so that the differences can be easily understood as shownin FIGS. 6B through 6E.

First, the (a) LH indicates that a power of a leading pulse of the erasepattern is the same as the low level Pb1 of the following pulse of theerase multi-pulse, and when a last pulse of the erase multi-pulse of theerase pattern ends at the low level Pb1, the power level of thefollowing Tsfp is the same as the high level Pb2 of the erasemulti-pulse. The (b) HH indicates that the power of the leading pulseforming the erase pattern is the same as the high level Pb2 of thefollowing pulse of the erase multi-pulse, and when the last pulse of theerase multi-pulse of the erase pattern ends at the high level Pb2, thelevel of the following Tsfp continues to be the same high level Pb2 ofthe erase multi-pulse. The (c) HL indicates that the power of theleading pulse forming the erase pattern is the same as the high levelPb2 of the following pulse of the erase multi-pulse, and when the lastpulse of the erase multi-pulse of the erase pattern ends at the highlevel Pb2, the level of the following Tsfp is the same as the low levelPb1 of the erase multi-pulse. Finally, the (d) LL indicates that thepower of the leading pulse forming the erase pattern is the same as thelow level Pb1 of the following pulse of the erase multi-pulse, and whenthe last pulse of the erase multi-pulse of the erase pattern ends at thelow level Pb1, the level of the following Tspf continues to be the samelow level Pb1 of the erase multi-pulse.

FIGS. 7A and 7D are other examples LH2 and LH3 of LH of FIG. 6B.Referring to FIGS. 7A and 7D, the (e) LH2 is the same as (a) LH of FIG.6B, except that Temp1, a duration time of the high level Pb2 of themulti-pulse forming a cycle, is 0.7 Ts and Temp2, a duration time of thelow level Pb1 of the multi-pulse, is 0.3 Ts. Also, the (f) LH3 is thesame as (a) LH of FIG. 6B, except that the duration time of the highlevel Pb2 or the low level Pb1 of the multi-pulse is 1.0T. Here, a ratioof Temp1 and Temp2, that is, the ratio of the duration time of the highlevel Pb2 and that of the low level Pb1 of the multi-pulse forming acycle can be changed as m:n in a variety of ways. (Here, m and n areintegers.) Thus, the recording waveform has the erase pattern containingthe multi-pulse (erase multi-pulse) of which power is the high level Pb2or the low level Pb1, and therefore distortion of the trailing edge ofthe mark is prevented and the reproducing characteristic of the opticaldisc is improved. In particular, in the recording waveforms shown in theembodiments described above, the duration time of the high level Pb2 andthe low level Pb1 of the multi-pulse is adjusted within a range between0.25 Ts and 0.75 Ts for a clock cycle T, and a duration time appropriateto heat characteristic of the optical disc 200 is selected. Therefore,the reproducing characteristic of the optical disc is more improved.

Meanwhile, information on the four types of the erase patterns (typeinformation) may be recorded in a lead-in area of a recordable disc(optical disc) or may be included in a wobble signal as one of headerinformation items. In this case, when data are recorded, the recordingapparatus reads type information from the lead-in area or from thewobble signal to form the mark or the space by generating acorresponding recording waveform.

In addition, the four types of the erase patterns may be used as asymbol indicating multiple times speed of the disc or the kind of themark when data is recorded and reproduced. For example, the erasepattern may indicate information of “the speed of a disc using LH typeerase pattern is 20-multiple times speed.”

In order to test an effect of the examples described herein, shapes ofthe mark recorded in a simulation were observed. A structure used in thesimulation is shown in table 1. The disc used in the simulation has a4-layered film structure.

TABLE 1 Dielectric Recording Dielectric Reflecting Substrate film filmfilm film Material PC ZnS—SiO₂ Sb—Te ZnS—SiO₂ Ag alloy eutectic Thick-0.6 mm 128 nm 14 nm 16 nm 30 nm ness

Each condition of the simulations includes a wavelength of 405 nm, anumeral aperture (NA) of 0.65, and a linear velocity of 6 m/s. In orderto observe the shape of the mark, after a recording mark of 8T isrecorded, a next recording mark of 8T is recorded by overlapping 4T ofthe previous recording mark of 8T. FIGS. 8A through 10C show comparisonresults between the mark shapes when the prior art recording waveformwas used and the mark shapes when the recording waveform according toexamples described herein was used. FIG. 8A, shows a mark (a) formed bythe simulation, FIG. 8B shows a mark (b) formed on the mark (a) by arecording waveform according to examples described herein, and FIG. 8Cshows a mark (c) formed on the mark (a) by the prior art recordingwaveform. Likewise, FIG. 9A shows a mark (d) formed by the simulation,FIG. 9B shows a mark (e) formed by the recording waveform having theerase pattern according to examples described herein, and FIG. 9C showsa mark (f) formed by the recording waveform having the prior art DCerase pattern. FIG. 10A shows a mark (g) formed by the simulation, FIG.10B shows a result of erasing the mark (g) by the erase patternaccording to examples described herein, and FIG. 10C shows a result oferasing the mark (g) by the prior art DC erase pattern.

Table 2 shows parameters of thin films of the optical disc used inanother simulation for interpreting heat.

TABLE 2 λ = 405 nm Material n K C(J/cm³K) k(W/cmK) ZnS—SiO₂ 2.300 0.0002.055 0.0058 Sb—Te eutectic 1.650 3.150 1.285 0.0060 (Crystal) Sb—Teeutectic 2.900 2.950 1.285 0.0060 (Amorphous) Ag alloy 0.170 2.070 2.4500.2000

Referring again to simulation results of FIGS. 8A through 10C, it isshown that the trailing edge of the mark (b) formed by the recordingwaveform having the erase pattern according to examples described hereinas shown in FIG. 8B is better than the trailing edge of the mark (c)formed by the recording waveform having the prior art DC erase patternof the prior art method as shown in FIG. 8C Like the trailing edges, theshape of the leading edge of the mark is better when the erase patternaccording to examples described herein as shown in FIG. 9B. The resultsof the simulation show that the shape of the mark when the recordingwaveform having the erase pattern formed with the erase multi-pulse isused, is improved compared with the prior art. By adjusting the shape,width, and power level of the erase multi-pulse, distortion of the shapeof the mark can be more reduced.

In order to experimentally verify the effect of examples describedherein, parameters needed in obtaining the recording waveforms shown inFIGS. 4A through 5C, that is, the duration time and the power level,were obtained from a 4.7 GB DVD-RAM disc and a 4.7 GB DVD-RW disc usinga DVD evaluator of which the laser wavelength is 650 nm and the NA is0.60. Then, characteristics of repetitive recording/reproducing the NRZIdata signal according to examples described herein were compared withthe prior art method.

FIGS. 11A through 15 are graphs showing the characteristics of theDVD-RAM. FIGS. 11A through 13B show features of power and time ofrecording the NRZI data signal using the recording waveform with the DCerase pattern of the prior art, and FIGS. 14A, 14B, and 15 show improvedfeatures of recording the NRZI data signal using the recording waveformof examples described herein. FIGS. 11A and 11B show jittercharacteristics with respect to recording power and erase power,respectively, for the leading edge, trailing edge, and both edges of themark in the prior art DC erase. Based on the jitter characteristics,14.5 mW recording power and 6 mW erase power were selected forexperiments.

FIGS. 12A through 13B show the measured results in the prior art DCerase. Referring to FIGS. 12A-12G and FIGS. 13A and 13B, the mostpreferable jitter characteristics are shown when Tsfp=0.5 Ts and whenTsfp=0.4 Ts. Tcl didn't affect the jitter characteristics, and Tlp wasgood when the cycle is 0.7 Ts.

Based on the parameters experimentally obtained in this way, the markwas formed with the recording waveform having the four types of erasepatterns described above, and the characteristics of the formed markwere measured as the following.

FIGS. 14A and 14B show the jitter characteristics of the four typesshown in FIG. 6. Referring to FIGS. 14A and 14B, it can be inferred thatjitter characteristic is good when the NRZI data signal is recordedusing the recording waveform with the erase pattern, i.e., any one ofthe four types of the erase pattern shown in FIGS. 6A-6E. Especially,referring to FIG. 14A, it is shown that the LH type is the best amongthe four types. Referring to FIG. 14B, when the erase pattern formedwith the erase multi-pulse according to examples described herein isused in erasing the mark, the jitter characteristics of ΔPb (Pb2−Pb1),which is a difference between the high level and the low level of theerase multi-pulse, is shown. It is shown that up to 5 mWs there is nobig difference.

FIG. 15 shows the jitter characteristics of the results of repetitiverecording/reproducing using the recording waveform having the erasepattern according to examples described herein compared with the priorart. Referring to FIG. 15, it is easily understood that when the mark iserased using the erase multi-pulse according to examples describedherein, the result is good, especially in the repetitive recordingcharacteristics aspect.

FIGS. 16A through 20 are graphs showing characteristics of the DVD-RW.FIGS. 16A through 18B show features of power and time of recording theNRZI data signal using the recording waveform with the DC erase patternof the prior art, and FIGS. 19A through 20 show improved features ofrecording the NRZI data signal using the recording waveform of thepresent invention examples described herein.

FIGS. 16A and 16B show jitter characteristics with respect to recordingpower and erase power, respectively, for the leading edge, trailingedge, and both edges of the mark in the prior art DC erase. Based onFIGS. 16A and 16B, 14.0 mW recording power and 6 mW erase power wereselected.

FIGS. 17A through 18B show the measured results in the prior art DCerase. Referring to FIGS. 17A through 18B, the most preferable jittercharacteristics are shown when Tsfp=0.3 Ts and when Tsfp=0.05 Ts. Tclwas good in 0.55 Ts, and Tlp was good in 1.0 T and 1.1 Ts.

Based on the parameters experimentally obtained in this way, the markwas formed with the recording waveform having the four types of erasepatterns described above, and the reproducing characteristics of theformed mark were measured as the following.

FIGS. 19A and 19B show the jitter characteristics of the four typesshown in FIGS. 6B through 6E. Referring to FIG. 19A, it is shown thatthe LH type is the best among the four types. When the erase patternformed with the erase multi-pulse is used in erasing the mark, thejitter characteristics of ΔPb(Pb2−Pb1) which is the difference betweenthe high level and the low level of the erase multi-pulse is shown.Since the characteristics are suddenly degraded from 3 mW, 1 mW wasselected as a condition for the repetitive recording/reproducingexperiment.

FIG. 20 shows the jitter characteristics of the results of repetitiverecording/reproducing the NRZI data signal using the recording pulsehaving the erase pattern. Referring to FIG. 20, it is easily understoodthat when the mark is erased using the erase multi-pulse, the result isgood, especially in the repetitive recording characteristics aspect.However, the jitter characteristics were suddenly degraded from 2,000times. Therefore, it is shown that the pulse erase method according tothe present invention is may be advantageous up to 1,000 timesrepetitive recording that is guaranteed in the normal DVD-RW.

Meanwhile, the above experiments followed the DVD formats and thereforethe EFM+ modulation method was used. However, if any of other modulationmethods that are normally used, for example, the RLL(1, 7) method, theD(8-15) method, and the Dual modulation method, is used, the result willbe the same.

An example of a recording method based on the structure described abovewill now be explained.

FIG. 21 is a flowchart showing the recording method. Referring to FIG.21, the recording apparatus receives data from the outside source,modulates the data, and generates the NRZI data signal in operation1801. Then, the recording apparatus generates the recording waveformhaving the erase pattern containing the erase multi-pulse in operation1802. Using the generated recording waveform, the mark or the space isformed on the optical disc 200 in operation 1803.

According to the examples described above, the method of and apparatusfor recording data using the recording waveform prevents distortion ofthe shape of the mark occurring due to heat interference and heataccumulation when data is recorded, and improves the shape of the markso that the characteristics of recording/reproducing of the data areimproved.

A number of examples have been shown and described above. Nevertheless,it will be understood that various changes may be made. Accordingly,other implementations are within the scope of the following claims.

What is claimed is:
 1. An information storage medium which stores datarecorded using a waveform, comprising information on a recording patternof the waveform and an erase pattern of the waveform, wherein: therecording pattern comprises a beginning pulse, a multi pulse, and acooling pulse; the erase pattern comprises a first pulse and a multipulse having a first power level and a second power level; and theinformation comprises: first information on a power level of the firstpulse of the erase pattern connected to an end of the cooling pulse;second information on a power level of a period between a point whereNon Return to Zero Inverted (NRZI) data is transited from a low level toa high level and the beginning pulse of the recording pattern; thirdinformation which is used to obtain a duration of a period correspondingto the first power level of the multi pulse in the erase pattern; andfourth information which is used to obtain a duration of the periodbetween the point where Non Return to Zero Inverted (NRZI) data istransited from the low level to the high level and the beginning pulseof the recording pattern.
 2. The information storage medium of claim 1,wherein the power level of the first pulse of the erase patternconnected to the end of the cooling pulse is one of the first powerlevel and the second power level of the multi pulse of the erasepattern.
 3. The information storage medium of claim 1, wherein the powerlevel of the period between the point where Non Return to Zero Inverted(NRZI) data is transited from the low level to the high level and thebeginning pulse of the recording pattern is one of the first power leveland the second power level of the multi pulse of the erase pattern. 4.The information storage medium of claim 1, wherein a power level of thecooling pulse of the recording pattern is different from a power levelof the first pulse of the erase pattern.
 5. The information storagemedium of claim 1, wherein a power level of the cooling pulse of therecording pattern is less than a power level of the first pulse of theerase pattern.
 6. The information storage medium of claim 1, wherein apower level of the cooling pulse of the recording pattern is differentfrom the first and second power levels of the multi pulse of the erasepattern.
 7. The information storage medium of claim 1, wherein a powerlevel of the cooling pulse of the recording pattern is less than thefirst and second power levels of the multi pulse of the erase pattern.8. The information storage medium of claim 1, wherein the power level ofthe period between the point where NRZI data is transited from the lowlevel to the high level and the beginning pulse of the recording patternis different than a power level of the cooling pulse of the recordingpattern.
 9. The information storage medium of claim 1, wherein the powerlevel of the period between the point where NRZI data is transited fromthe low level to the high level and the beginning pulse of the recordingpattern is greater than a power level of the cooling pulse of therecording pattern.
 10. An apparatus for forming a waveform comprising arecording pattern and an erase pattern, the recording pattern comprisinga beginning pulse, a multi pulse, and a cooling pulse, and the erasepattern comprising a first pulse and a multi pulse having a first powerlevel and a second power level, to record data on an information storagemedium, the apparatus comprising: a reader which reads first informationon a power level of the first pulse of the erase pattern connected to anend of the cooling pulse, and second information on a power level of aperiod between a point where Non Return to Zero Inverted (NRZI) data istransited from a low level to a high level and the beginning pulse ofthe recording pattern, from the information storage medium; and acontroller which forms the waveform using the first information and thesecond information, wherein the information storage medium furthercomprises third information which is used to obtain a duration of aperiod corresponding to the first power level of the multi pulse in theerase pattern and fourth information which is used to obtain a durationof the period between the point where Non Return to Zero Inverted (NRZI)data is transited from the low level to the high level and the beginningpulse of the recording pattern.
 11. The apparatus of claim 10, whereinthe power level of the first pulse of the erase pattern connected to theend of the cooling pulse is one of the first power level and the secondpower level of the multi pulse of the erase pattern.
 12. The apparatusof claim 10, wherein the power level of the period between the pointwhere Non Return to Zero Inverted (NRZI) data is transited from the lowlevel to the high level and the beginning pulse of the recording patternis one of the first power level and the second power level of the multipulse of the erase pattern.
 13. The apparatus of claim 10, wherein thefirst information comprises one or more value, the second informationcomprises one or more value, and the controller selects the valueaccording to a recording speed.
 14. The apparatus of claim 10, wherein apower level of the cooling pulse of the recording pattern is differentfrom a power level of the first pulse of the erase pattern.
 15. Theapparatus of claim 10, wherein a power level of the cooling pulse of therecording pattern is less than a power level of the first pulse of theerase pattern.
 16. The apparatus of claim 10, wherein a power level ofthe cooling pulse of the recording pattern is different from the firstand second power levels of the multi pulse of the erase pattern.
 17. Theapparatus of claim 10, wherein a power level of the cooling pulse of therecording pattern is less than the first and second power levels of themulti pulse of the erase pattern.
 18. The apparatus of claim 10, whereinthe power level of the period between the point where NRZI data istransited from the low level to the high level and the beginning pulseof the recording pattern is different than a power level of the coolingpulse of the recording pattern.
 19. The apparatus of claim 10, whereinthe power level of the period between the point where NRZI data istransited from the low level to the high level and the beginning pulseof the recording pattern is greater than a power level of the coolingpulse of the recording pattern.